Generally, a sufficient supply of oil is essential for friction plate clutches to sufficiently lubricate components that rotate relative to one another, and to discharge friction-generating heat. On the other hand, a high oil volume flow leads to drag moments and thus to undesirable losses.
From U.S. Pat. No. 8,388,486 B2 a driveline of a motor vehicle is known with a disconnectable propeller shaft, wherein a first clutch is arranged in the performance path in front of the propeller shaft and a second clutch behind the propeller shaft. The second clutch is provided in the form of a friction clutch running under wet conditions, which clutch can be operated by a ball ramp assembly. A valve is provided for reducing the oil flow to the friction plate clutch when the propeller shaft is disconnected. The valve cooperates with a lubrication pipe which is fixed in the housing and which supplies the friction clutch with oil.
DE 101 50 704 A1 proposes a plate clutch for motor bicycles, which clutch comprises a hollow-cylindrical clutch shaft and a regulator for controlling the oil flowing in the clutch shaft. The regulator comprises a valve with a tappet and an aperture, which valve is arranged inside the clutch shaft. The tappet is connected to an axially movable disengagement element of the plate clutch. In the coupled condition of the plate clutch, the tappet in a position approaching the aperture, which corresponds to a low oil volume flow and in the uncoupled condition it is in a position where it is moved away from the aperture, which corresponds to a greater oil volume flow.
From DE 697 25 150 T2 a disc clutch assembly is known with an inner plate carrier and an outer plate carrier. The outer plate carrier comprises a toothed structure in which the outer plates are held in a rotationally fixed and axially movable way. In the region of the tooth gaps of the toothed structure, radial through-openings are provided over the circumference through which lubricating oil can flow radially outwardly to de-oil the clutch.
From DE 10 2011 086 376 B4 an oil supply device is known for a plate brake in a transmission module. For cooling purposes with the plate brake being in slip condition, an oil injection is provided which is controlled by a valve regulator. The supply of oil only takes place in operational slip phases of the plate brake. The valve regulator can be coupled to the signal of the piston control means of the multi-plate brake.
WO 2015 150 407 A1 proposes a drive assembly for a motor vehicle having an electric motor, a multi-stage transmission and a differential gearing. The multi-stage transmission comprises two transmission stages for driving the differential gearing under different transmission ratios. The transmission stages can be switched by a controllable switching unit which is arranged coaxially relative to the driveshaft. The driveshaft comprise a bearing bore as well as a plurality of transverse bores for supplying the seat portions of the gears arranged on the driveshaft and the switching unit.